The agreements will infuriate Microsoft which is struggling to get its own virtualisation offering onto the market.

VMware said that, under the agreement – financial terms of which remain secret – its ESX 3i hypervisor will be embedded in servers produced by the four manufacturers.

Hardware loaded with VMware's virtualisation software, which currently holds the number one spot in the global market, will begin shipping within the next 60 days, said the Palo Alto-based firm in a statement.

It’s a huge deal for VMware, with the announcement doubtless timed to overshadow Microsoft’s launch of Windows Server 2008 tomorrow, which gets the jamboree treatment – minus its own virtualisation software Hyper-V, which was previously code-named Viridian.

VMware’s Diane Greene described the deal as “a big step for the ubiquity of virtualisation”, according to today’s Financial Times. That somewhat inflates the software’s actual uptake within the corporate world, where fewer than ten per cent of servers currently use the technology.

What’s more significant is the fact that leading server makers have decided to bed down with VMware rather than await Microsoft’s delayed Hyper-V, which is expected to land within the next 180 days. ®